The present invention relates to a land vehicle with the structure which comprises a pillar fixed in position in a novel manner.
The majority of land vehicles have pillars which are called xe2x80x9cAxe2x80x9d pillars. These are the pillars which extend either side of the front windscreen of a vehicle and which support the roof of the vehicle (if the vehicle has one), which can provide support for the door frames of the vehicle and which, most importantly, provide crush resistance which protects the integrity of the cabin of the vehicle in the event that the vehicle is rolled over on its roof.
Typically land vehicles are made of steel and the roof pillars are steel pillars which are welded to the remainder of the structure of the vehicle.
Carbon fibre composite components have structural properties which are preferable to the properties of steel and which are suited to an xe2x80x9cAxe2x80x9d pillar. However, it has always been considered that it is difficult to integrate carbon fibre composite xe2x80x9cAxe2x80x9d pillars with the remainder of the vehicle structure.
The present invention provides a land vehicle having a pillar which is a structural component of the vehicle and a pillar support structure, the pillar being a distinct independent component not formed integrally with any surrounding components of the land vehicle, wherein the pillar is secured in position by setting of a root portion of the pillar in resinous material provided in a cavity defined in the pillar support structure.
It is a novel approach to set in position an xe2x80x9cAxe2x80x9d pillar using a resin. Usually the xe2x80x9cAxe2x80x9d pillars are steel and are welded in position. Otherwise, an approach could be taken to produce an xe2x80x9cAxe2x80x9d pillar with a root portion which has a shape which matches very closely the shape of a socket defined in its support structure, the root portion being slotted into the socket and perhaps adhered in position using an adhesive. However, this involves considerable expense in producing a correctly placed socket and it is not possible to adopt this approach without constraining to some degree the shape of the root portion of the xe2x80x9cAxe2x80x9d pillar, because the root portion must slide into a matching socket. This is not ideal. To avoid all of these problems, the xe2x80x9cAxe2x80x9d pillar of the present invention is set in place in resin, the resin being present in a cavity which is significantly larger in cross-section than the cross section of the xe2x80x9cAxe2x80x9d pillar.
Preferably the resinous material comprises an epoxy resin. However, the resinous material could equally well comprise a polyurethane resin.
Preferably the resinous material comprises hollow microspheres dispersed in a resin matrix. Preferably the hollow microspheres are glass microspheres. A block of resin of significant volume can be quite heavy. This is disadvantageous. In order to ameliorate this disadvantage it is preferred that microspheres are dispersed in the resinous material, in order to reduce the density of the resinous material and thereby reduce the overall weight of the block of resin used to set the xe2x80x9cAxe2x80x9d pillar.
Alternatively, the resinous material could comprise epoxy resin mixed with particulate silica. The use of particulate silica has an advantage during curing of the resin. The curing is an exothermic process and the silica helps keep the overall temperature to levels which avoid problems of stresses and cracking caused by thermal expansion and subsequent contraction.
As mentioned above, the pillar will preferably have a cross-section which varies along the length thereof, but for simplicity the cavity will generally have a constant cross-section along its length.
By choosing the cross-section of the cavity to be sufficiently large the invention can permit a situation in which the cavity has a principal axis and the pillar is set at an angle to the principal axis. This avoids the need for a socket machined at the particular angle in order to ensure correct positioning of the xe2x80x9cAxe2x80x9d pillar extending therefrom.
Preferably, the pillar comprises fibres set in a resin matrix. Preferably the pillar has a core of foamed material around which the fibres are wound with the core being encased by the resin matrix. The use of a core increases the overall weight of the pillar without reducing significantly its structural abilities.
Preferably the fibres used for the pillar are carbon fibres.
Preferably the land vehicle has an aluminium chassis and the pillar is an xe2x80x9cAxe2x80x9d pillar of the vehicle which is set in a cavity defined in the aluminium chassis. It would be particularly pertinent to use the present invention when the aluminium chassis is made of extruded components glued together. It would be easy to define the cavity by using an extrusion.
Preferably the land vehicle has as pair of pillars spaced apart one each side of a windscreen, the pair of pillars being secured in position one each in a pair of spaced apart cavities, the pillars providing crush resistance in the event of the land vehicle rolling over.
Preferably the land vehicle also comprises a crush tube mounted adjacent to the pillar and covered in a flexible material, the crush tube being located to prevent the head of an occupant of the land vehicle hitting directly a pillar in the event of a vehicle collision, the crush tube deforming to absorb impact energy in such an event.
In one embodiment the crush tube is an aluminium crush tube and in a second embodiment the crush tube is a cardboard crush tube. Preferably the crush tube is covered by a sheet of ABS plastic material.
The present invention also provides a method of manufacture of the land vehicle described above in which the pillar is positioned with the root portion thereof extending into the cavity in the pillar support structure, the resinous material in liquid state is poured into the cavity surrounding the root portion of the pillar, the resinous material is cured and the cured resinous material then secures the pillar in position.
Where the pillar has a core of foamed material it is preferably formed by first of all forming the core of foamed material in a desired shape with a cross-section which varies lengthwise along the core, then winding the fibres around the core of foamed material, setting the wound fibres in a resin matrix and thereby encasing the core of foamed material.